Release relief valve



C. A. ELLIS E LLIS ATTNE E Aug. 18, 1959 RELEASE RELIEF VALVE OriginalFiled Jan.

90 0 6 Oo 7 .m

United States Patent "P RELEASE RELIEF VALVE Charles A. Ellis, Hamden,Conn., "assignor to American Optical Company, Southbridge, Mass., avoluntary association of Massachusetts Original application January 12,1949, Serial No. 70,499, now Patent No. 2,711,632, dated January 28,1955.

Divided and this application January 7, 1955, Serial 1 2 Claims. (Cl.IS7-599.2)

so as to insure safe operation of said systems without damage tomechanisms operated thereby in the event of failure of said mechanismsto function properly, together with metering means for controlling therate of ow of a iluid through said valve.

A further object of the invention is to provide a releaserelief valve ofthe above character for use in hydraulic systems which is relativelyinexpensive, comparatively simple in its construction and eicient in itsoperation.

Other objects and advantages of the invention will become apparent fromthe following description taken in connection With the accompanyingdrawings, in which:

Fig. l is a longitudinal cross-sectional view of the device of theinvention and of a lift mechanism in operatively connected relation withsaid device.

Referring to the drawings wherein like characters of reference designatelike parts throughout the several views, the invention is embodied in ahydraulic release-relief valve 10 mounted on a base 25 having avertically disposed hydraulic lift cylinder 23 thereon. While otherhydraulic mechanisms can be operated by the device of the invention, thelift cylinder 23 will be described herein for purposes of illustratingthe invention.

A vertically disposed tubular support 22 is placed over the hydrauliclift cylinder 23 and its upper end is adapted to carry articles to belifted by the cylinder 23.

The base 25 has a partially threaded opening 33 formed in its uppersurface in which is threaded the lower end of an inner tubular member 34(Fig. 4) and has a cap 35 threadedly mounted over its upper end, the cap35 being of larger diameter than the tubular member 34 and formed with aperipheral shoulder 35a` against which the upper end of the outerhydraulic lift cylinder 23 is adapted to abut, with the lower end of thecylinder 23 being disposed within a circular ring-like boss 36 formed onthe upper surface of the supporting disc and encircling the opening 33therein. Thus, there is formed an inner chamber 37 within the tubularmember 34 and a reservoir 38 externally of the member 34 but within thecylinder 23, with oil seals 39 provided adjacent the areas of connectionbetween the parts of the device to prevent leakage of oil or other fluidfrom the chamber 37 or reservoir 38. The reservoir can be lled through avertical opening 35a provided through the cap 35, which opening issealed by a threaded plug 35b.

A piston 40 is mounted for vertical movement within the inner chamber 37and has a rod 41 extending therethrough, with a portion of the rod 41projecting beneath the piston 40, the portion of the rod 41 inside thepiston Patented Aug. 18, 1959 ICC 40 being reduced in size to form ashoulder 42 against which the upper surface of the piston rests, withmeans such as a castellated nut and cotter pin arrangement 43 locatedover the lower end of the rod 41 to retain the piston 40 in Iplace. Theupper portion of the rod 41 is of a length to extend upwardly through anopening in the cap member 35 and has a depression 44 formed in its upperend in which is seated a ball member 45. A hub 46 provided with a hollow48 therein is formed on the under side of a disc 47 and is mounted overthe upper end of the rod 41 with the bottom of the hollow 48 resting onthe ball 45. The disc 47 has a resilient disc 49 of rubber or otherresilient material secured to its upper surface which serves toresiliently support the tubular support 22 which is concentricallylocated with clearance about the cylinder 23 and vertically movable overit. The disc 49 serves to mechanically isolate the support 22 so that novibration will be transmitted to an article being lifted by the support22 from the operative units within the lift cylinder. Oil seal-s 50 areprovided in the piston 40 and cap member 35 for preventing leakage offluid, similarly to the seals 39 and a series of openings 34a areprovided adjacent the upper end of the member 34 to permit escape of anyfluid which might manage to find its way into the chamber 37 above thepiston 40.

The valve 10 of the invention embodies a cylindrical housing 69 mountedvertically on the base 25 adjacent the lifting cylinder 23 and securedthereto as by bolts 70. The housing 69 is closed at its upper end and isdisposed with its lower end over an opening 71 leading to a highpressure conduit 59 in the base 25 which communicates with the chamber37 of the lifting cylinder 23. The opening 71 is threaded for receptionof a. plug 72 which is screwed therein and which is provided with acentral vertical bore 73 therethrough, the bore having a beveled upperedge indicated by the numeral 74.

A vertically extending tubular member 75 is provided with a lower endportion 76 of a size and shape to t within the bore 73 in the plug 72and having a beveled portion 74 shaped to rest evenly upon the bevelededge 74a of the plug bore 73 as a valve seat. The tubular member 75 hasa high pressure chamber 77 therein into which fluid under high pressurefrom conduit 59 is permitted to pass through bores 73 and 71. Thehousing 69 is preferably formed as separate upper and lower sectionsjoined as at 78 so that the adjacent abutting portions may be threadedinternally for reception of a block 79 having a vertical bore 80therein.

A plug 81 is threaded into the upper end of the tubular member 75 andhas a vertical bore 82 therein, concentric with and of smaller diameterthan the upper portion of the chamber 77. The chamber 77 has a coiledspring 83 disposed therein for retention of a ball plug member 84 overthe lower end of the bore 82 in the plug 81, the lower end of the spring83 being adapted to rest upon shoulder 84a formed by a bore 84hcommunicating with the lower end of the chamber 77, which bore 8417 alsocommunicates with the bore 73. Thus, fluid will be permitted to enterthe chamber 77 from conduit 59 through bores 71, 73 and 84d but will beprevented from leaving by the ball 84 which is held over the end of thebore 82 by the spring 83. A coil spring 85 encircles the tubular member75 and has its upper end disposed in a groove 86 formed in the lowersurface of the block 79, its lower end resting upon the shoulder formedby an enlarged portion 87 of the tubular member 75. Thus, the tubularmember 75 is continually urged downward by the spring to provide a sealbetween the adjacent conical surfaces 74 and 74a formed on the endportions 76 thereof and the opening 73 in the plug 72.

In the event that an excessive uid pressure is built up in the highpressure conduit S9 and the extent of the pressure is such as toovercome the tension of the spring 85, the tubular member will be forcedupwardly within the block 79. This will draw the lower end portion 76 ofthe tubular member upwardly, providing a space between the conicalsurfaces 74 and 74a, which will permit the uid to pass from the highpressure chamber 77 into a low pressure chamber 88 formed by the wallsof the housing 69, thus relieving the pressure within the chamber 37 ofthe lift cylinder and the chamber 77 of the valve 10. 'Ihe uid thenpasses through one or more openings 89 provided in the base 25 whichcommunicate with a conduit 90, one end of which opens into the reservoir38 within the lift cylinder 23. Thus, the uid can flow tothe reservoir38 directly from the low pressure chamber 88.

Conventional oil seals 93 are provided within the housing 69 at variouspoints for preventing leakage of the hydraulic uid at these points.

The valve 10 further includes a metering arrangement for lowering thelift cylinder from a raised position at a controlled rate of speed.

The metering arrangement embodies a rod 98 extending vertically throughan opening in the top of the housing 69. Which is adapted to be mountedfor vertical movement in the housing 69. The lower end of the rod 98 ispositioned in a vertical opening in the upper end of the block 79 andhas a collar 99 fixedly secured thereto as by a pin 100. The collar 99having a flange 101 formed integral therewith, is adapted to restagainst the under surface of the top of the housing 69. A coiled spring102 is positioned about the rod 98 with its upper end resting againstthe flange 101 of the collar 99 and with its lower end abutting theblock 79. Thus, the spring 102 will serve to maintain the rod 98 inposition as illustrated in the drawing.

The lower end of the rod 98 is provided with a depression 103 of a sizeand shape for reception of the upper end of a vertically disposed valveoperating member 104. The member 104 is of such length as to be spacedslightly away from the bottom of the recess 103 at its upper end toallow a slightly play between the parts of the device, and has its lowerportion extending through the bore 82 in the plug 81 carried by theupper end of the tubular member 75, with its lower end resting againstthe ball 84 sealing the end of the bore 82. The lower end of the rod 104is of a diametrical size substantially that of the bore 82 but tapersupwardly to a thin portion approximately midway thereof. Thus, bydepressing the rod 98, the bottom of the recess 103 in the rod 98 willengage the upper end of the member 104 and will force it downwardly.This downward movement of the member 104 will also push the ball 84downwardly against the tension of the spring 83 and, due to the taper ofthe member 104, fluid from the high pressure chamber 77 will ow into thebore 82 and from there it will proceed through a series of openings 105in the plug 81 into the low pressure chamber 88, and from there into thereservoir 38 of the lift cylinder 23 through conduit 90.

It will be understood that upon relief of the high pressure within thechamber 77, this relief will also be felt by the fluid in the liftingdevice chamber 37. Thus, the the piston will be allowed to descend inaccordance with the amount of uid permitted to leave the chamber 37. Itwill also be understood that the speed at which the chair is permittedto be lowered may be controlled by the operator of the rod 98, since hecan control the distance which the valve operating member 104 will bedepressed and consequently control the amount of uid permitted to escapefrom the chamber 77. Due to the fact that the member 104 is providedwith a tapered portion, it is obvious that if the member 104 is urgeddownwardly to a considerable extent a considerable amount of the uidwill be permitted to pass into the bore 82, while if the member 104 ismoved only a slight distance downwardly, the amount of fluid passinginto the bore 82 will be small.

In the event that the lift cylinder is lowered fast it is possible thatthe conduit will be unable to accommodate the entire amount of fluidpermitted to escape at once from the high pressure chamber 77.Therefore, the block 79 is provided with a series of vertical bores 106therethrough so that the fluid can also temporarily pass upwardly intothe space formed in the upper portion of the housing 69 above the block79.

The invention provides an improved release-relief valve as safety meansfor preventing damage to hydraulic systems in the event that excessiveor damaging fluid pressures occur in said systems and also providesmetering means under the control of an operator for controlling theextent of downward movement of a lift cylinder or the like and the speedat which the cylinder is lowered.

It is to be understood that the mechanism described hereinabove may beused with articles other than lift cylinders and is adaptable to varioustypes of hydraulic systems.

While the novel features of the invention have been shown and describedand are pointed out in the annexed claims, it will be understood thatvarious omissions, substitutions and changes in the formation anddetails of the device illustrated, and in its operation, may be made bythose skilled in the art without departing from the spirit of theinvention.

Having described my invention, I claim:

1. A hydraulic release-relief valve comprising a solid outer wall casinghaving a centrally disposed uid inlet port in the base thereof and atleast one iluid outlet port also in said base spaced from said inletport, a tubular member dividing the interior of said casing into a pairof pressure chambers, said tubular member resting on the base of saidcasing when in normally closed position and having a central boretherein forming one of said pressure chambers, said central bore beingin communication with said inlet port, said outlet port communicatingwith the other of said chambers, the central bore of said tubular memberhaving an elongated upper section of reduced cross-sectional size, alongitudinally adjustable gate means disposed in said upper section,said gate means embodying an enlarged closure portion within said boreof a cross-sectional size greater than that of said upper section fornormally closing the communication between said upper section and theremaining portion of said central bore and an elongated graduallytapering conical shank portion extending substantially throughout thelength of said upper elongated reduced section of the central bore, saidconical shank portion of the gate means having its end of greatestcross-sectional area substantially equal to the cross-sectional area ofthe elongated reduced upper section of said central bore and being inconnected relation with said enlarged closure portion thereof, saidtubular member having transversely disposed apertures extending betweensaid upper section of the central bore therein and said other of thechambers, operable means for adjusting said gate means longitudinally inthe upper reduced section of said central bore to open and closecommunication between the chambers in said casing whereby said graduallytapering conical shank portion will function to meter a ow of fluidthrough said communication in accordance with the extent to which saidgate means is adjusted in said upper section of said central bore in thetubular member, said tubular member being adapted for movement towardand away from the base of said casing, and spring means normally urgingsaid tubular member to remain at rest on said base, said spring meansbeing under such tension that when a fluid in the tubular member exceedsa maximum pressure the said pressure, in excess of said maximum, actingon said tubular member will overcome the tension of said spring meansand lift the tubular member of said base to permit a flow of said fluidinto said other chamber having an outlet port to reduce said pressureand allow the tubular member to return to its normal closed position.

2. A release-relief valve device for a hydraulic system comprising asolid outer wall casing set on a base and having a centrally disposedhigh pressure lluid inlet port in the base, a ltubular member of smallersize than the interior of said casing located therein and dividing saidcasing into a pair of pressure chambers, one of said pressure chambersbeing `the central rbore of said tubular member and the other of saidpressure chambers being the space between said tubular member and saidouter wall casing, said 'tubular member resting on said base with itscentral ibore communicating with said high pressure inlet port when inits normal closed position, said casing having a portion projecting intothe interior thereof and shaped to provide a slideway for receiving theupper end part of the tubular member, spring means surrounding thetubular member and resting on outwardly projecting means carried by thetubular member adjacent its lower end, the upper end of said springmeans pressing against said projecting portion of the casing undercompression, the ends of said central bore of the tubular member beingof smaller section than the main portion of said bore, said tubularmember having at least one transverse opening in its upper endcommunicating with said upper portion of the bore of reduced section andthe space between said tubular portion and the casing, said casingfurther having a low pressure outlet port communicating with said space,gate means located in the upper end of the main portion of the bore ofsaid tubular member, said gate means being of a size greater than thereduced section of said upper portion of said bore and operable to openand close communication between the main and upper por-tions of thebore, spring means having one end resting on the lower edge of the mainportion of the bore and compressing against said gate means to maintainit normally closed, elongated conically shaped metering means extendingsubstantially throughout Ithe length of the upper portion of said borewith its greatest area of cross-section adjoining said gate means and ofa diameter substantially equal to the diameter of said upper portion ofsaid bore, manipulatable means operatively connected with said meteringand gate means for depressing said metering and gate means by overcomingthe tension of the spring means urging the gate means to remain closedwhereby uid may be permitted to ow from the main port-ion of the bore ofthe tubular member, through said transverse opening in said tubularmember at controlled rates and in controlled amounts in accordance withthe `extent to which said metering and gate means are depressed, thespring means surrounding the tubular member having 4tension suflcient tocause said tubular member to remain at rest on said base against fluidpressure up to a predetermined value, whereby, pressure in excess ofsaid predetermined value will raise the tubular member, against saidspring tension, oil the base to permit a ilow of fluid from said highpressure inlet port into the space between the casing and tubular memberand through the low pressure outlet port of an amount suicient to allowthe tension of the spring to return the tubular member to its normalclosed position to automatically maintain a substantially constantpredetermined high pressure in said tubular member while said gate means'is closed.

References Cited in the file of this patent UNITED STATES PATENTS367,563 Vielhaber Aug. 2, 1887 433,543 Schreidt Aug. 5, 1890 1,326,124Vischer Dec. 23, 1919 1,688,092 Smith Oct. 16, 1928 2,565,050 Smith Aug.21, 1951 2,591,562 Levcll Apr. 1, 1952 2,621,631 Dowty Dec. 16, 19522,711,632 Ellis June 28, 1955 FOREIGN PATENTS 436,431 Great Britain Oct.10, 1935

